When Ronald Reagan chose to hang a portrait of Calvin Coolidge in the White House Cabinet room, he was making a policy statement: Coolidge was a seriously underrated president, and the 30th president had a view of taxation in sync with his own. Six decades earlier, Coolidge had branded taxation that was “not absolutely required” as “only a species of legalized larceny.”

In the 1980s, it was called “supply-side economics.” In the 1920s, the catchphrase (bestowed by Coolidge Treasury Secretary Andrew Mellon) was “scientific taxation.”

In what is easily one of the most authoritative biographies of the White House occupant who presided over most of the “Roaring Twenties,” Amity Shlaes has given us the 500-plus page volume “Coolidge.”

While some readers may be mildly annoyed by the book’s diary-like chronological telling of Calvin Coolidge’s life, many others will appreciate the opportunity to see the era as he saw it. Ms. Shlaes takes you through every facet of the president’s life as he experienced it. Short of an autobiography (one was recently re-released), the author takes you through most of Silent Cal’s life: his modest beginning in Plymouth Notch, Vt., his schooling, his family, his country lawyering and his eventual move to Northampton, Mass. It continues with his rise in public office from city councilman (in his mid-20s) to city solicitor, clerk of courts, state representative, mayor, state senator, state senate president, lieutenant governor and then — making national headlines — to governor, where he faced down a bitter strike by the Boston police force.

If there is one single comment by Gov. Coolidge that catapulted him to national office, it was what he wrote in a telegram to the AFL president at the height of the police walkout: “There is no right to strike against the public safety by anyone, anywhere, anytime.”

The striking officers — about three-quarters of the total force — were fired. Out-of-control vandalism and looting continued day and night, in a very real sense terrorizing much of the city. Rioters simply laughed at official orders that they cease and desist in their destruction and thievery. That added to the already-elevated public approval of the governor’s position. History would repeat itself when President Reagan fired illegally striking air traffic controllers in the ‘80s and in Wisconsin Gov. Scott Walker’s refusal to cave in to state capital demonstrations by government workers in 2011.

Coolidge went on to win the Republican nomination for vice president on a ticket headed by Warren Harding, a U.S. senator from Ohio. Americans were so disgusted with the skyrocketing taxes and fiscal mess left by Democrat Woodrow Wilson that the GOP’s Harding-Coolidge ticket won in a landslide. Upon Harding’s sudden death, Calvin Coolidge became president from 1923 until 1929.

Many writers and some historians glide over that era, as if very little of consequence happened during the Harding-Coolidge years beyond the failed enforcement of Prohibition (that had become law in 1919), the Charleston dance fad and Charles Lindbergh’s epic trans-Atlantic flight (duly honored by President Coolidge).

Herculean efforts were required to obtain congressional approval for tax cuts, and they had to be accomplished in steps starting in 1921 under Harding, then under Coolidge in 1924 (which aided “Silent Cal” in winning election to the presidency that year in his own right), and in 1928, one of Coolidge’s crowning achievements, after having announced he would not seek re-election.

Coolidge managed to get the top tax rate down to 25 percent, even lower than Reagan’s later 28 percent. Not only did prosperity follow, but the bulk of World War I debt was paid off. One reason for congressional reluctance to give the green light on the plan (beyond special-interest objections) was concern that Coolidge and Mellon were venturing into untried policy territory. Skepticism abounded about the idea that lower taxes would generate more revenue for the Treasury and lead to booming prosperity. The same hesitancy at first greeted Reagan’s prosperity-inducing “supply side” proposal, notwithstanding success of a similar program under Coolidge.

Ms. Shlaes presents the multidimensional Calvin Coolidge as possessing the inner strength to cope with the tragedy of his mother’s death when the future president was just 12, the passing of his younger sister six years later and the loss of his teenage son, Calvin Jr., during the White House years.

Charles Edward Garman, Coolidge’s professor of moral and mental philosophy at Amherst College, exerted a profound influence on the young man. Garman, the president would later say, was a man “who walked with God.”

Coolidge’s marriage to Grace Goodhue, an extrovert and very personable woman, was a real love story. In all matters, friends said of the dutiful husband, “Grace comes first.”

Ms. Shlaes‘ research is thorough and makes a convincing case for Calvin Coolidge as America’s most underrated 20th-century president.

Wes Vernon is a veteran broadcast journalist whose career included 25 years with CBS Radio.